the real problem isn’t the vehicle, it’s its speed and compared to the traffic around it.

I distinguished that speed of a vehicle itself is an issue and not primarily, as you stated, how its speed relates to traffic around it. A car that's going with the flow of traffic at 80km/h is still fatal to be hit by when you're walking or biking.

The real problem is speed, doesn’t matter how much mass or energy a vehicle can have if it’s not moving.

This shows a fundamental lack of understanding; a stationary vehicle has no kinetic energy. When you get hit by a car, the energy you are hit with (kinetic energy) depends on the mass and speed of the vehicle.

My dad got hit by a kid in a bicycle causing a wound that never really healed.

I'm sorry to hear that, it sounds like I really difficult experience. I fail to see how a child making a mistake while riding a bike is relevant to your claim that "the real problem isn’t the vehicle, it’s its speed and compared to the traffic around it." and how "cars have to slow down because of bicycles" is the cause of danger. Orders of magnitude more people and children die being hit by cars than any other form of transportation and the answer is not blaming people on bikes for collisions since they "made" cars change their speed relative to traffic around them.

People die from doing activities with risk, the answer is not to lock yourself in a room and live afraid

No such claim was made.

That you dismiss the utility of cars is more of a commentary of the bubble and environment you’ve had the opportunity to enjoy

Nobody is denying the utility of vehicles. Our infrastructure are designed with cars having absolute top priority, making short trips by bike and walking dangerous. Most trips in cities are short and doable by bike or walking, but when the infrastructure is poor and people perceive it to be an unacceptable risk, they take a car. How many times have you seen people riding on sidewalks because they don't feel that the line of painted bike lane protects them from a driver on their phone who could kill them? Or someone on a mobility scooter in a bike lane because the uneven, discontinuous sidewalk that lowers for cars at each crossing presents more danger of them falling over? I bike, I walk, and I drive; everything I've mentioned is the product of not living in a bubble, otherwise I wouldn't see the problems.

I'm starting to see ad hominem and straw man arguments, so I'm not going to put the energy into continuing this conversation. Enjoy the rest of your day. :)